The existence of the fourth passive circuit element was proposed by Prof. Leon Chua of UC Berkeley in 1971 from fundamental symmetry arguments to augment the familiar resistance, inductance and capacitance equations. Although he showed that such a ‘memristor' had many interesting and useful circuit properties, until 2008 no one had presented a physical model nor material example of such an element. In fact, memristance arises naturally in systems for which electronic and atomic/ionic transport are coupled under an external bias voltage. Simple analytical models show that memristance becomes much more important as the thickness of the active device region decreases, and thus memristors are mainly nanoscale structures that are difficult to produce as discrete devices. Memristor theory serves as the foundation for understanding a wide range of hysteretic current-voltage behavior observed, including both unipolar and bipolar switching, over the past 50 years in many electronic devices that involve the motion of atoms, vacancies or molecular components, which are now known as ReRAM or resistive-RAM devices. We have built nanoscale titanium dioxide and tantalum pentoxide memristors in our laboratory and have demonstrated both their fundamental electrical properties and several potential uses, including new forms of memory and logic circuits. Memristors can rather easily be integrated into electronic circuits using conventional fabrication techniques and materials available in standard CMOS fabrication facilities. In this talk, I will present some recent results on understanding device mechanisms as well as switching speed and energy measurements.
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About the speaker:
R. Stanley Williams is an HP Senior Fellow at Hewlett-Packard Laboratories, one of only six scientists in HP with this title. He received a B.A. degree in Chemical Physics in 1974 from Rice University and his Ph.D. in Physical Chemistry from U. C. Berkeley in 1978. He was a Member of Technical Staff at AT&T Bell Labs from 1978-80 and a faculty member (Assistant, Associate and Full Professor) of the Chemistry Department at UCLA from 1980 -- 1995. He joined HP Labs in 1995 to found the Quantum Science Research group, which originally focused on fundamental research at the nanometer scale. His primary scientific research during the past thirty years has been in the areas of solid-state chemistry and physics, and their applications to technology. In 2008, a team of researchers he led announced that they had built and demonstrated the first intentional memristor, the fourth fundamental electronic circuit element, complementing the capacitor, resistor and inductor. In 2010, he was named one of the first recipients of the newly created HP CEO's Award for Innovation. He has received other awards for business, scientific and academic achievement, including the 2009 EETimes Innovator of the Year ACE Award, the 2007 Glenn T. Seaborg Medal for contributions to Chemistry, the 2004 Herman Bloch Medal for Industrial Research, and the 2000 Julius Springer Award for Applied Physics. He has over 120 US patents and 370 papers in reviewed scientific journals.
For further information about HP Labs: http://www.hpl.hp.com/about and Stan William's Offical Biography.
R. Stanley Williams